Method of making jar closures



April 26, 1938. w KOWAL 2,115,310

METHOD OF MAKING JAR CLOSURES v Filed July 51, 1936 J0 V I J0 corners thereof Patented Apr. 26, 1938 UNITED STATES PATENT OFFICE Phoenix Metal Cap Company, Inc.,

Chicago,

Ill.. a corporation of New York Application July 31, 1936, Serial No. 93,706

3 Claims.

This invention relates to a new and improved method of making jar closures, its chief utility being in connection with caps of the double shell type.

I-Ieretofore, in the manufacture of metal caps of this type, it has been the usual practice to shape the inner shell from a circular blank, curl the edge thereof and then assemble the inner shell inside of the outer one.

.In die-cutting the circular blanks, it is generally considered the best practice to use a layout of regularly spaced circles, with a definite bridge between adjacent blanks to permit the punches to cut them and to leave the scrap in one piece for convenience in handling and to be sure that'no loose chips are permitted to fall into the die.

The sheet is usually first cut into strips for a single row layout or for staggered rows in a double or triple die layout. Not only does the circular shape of the blank entail a considerable percentage of Waste metal, but the smooth contour of the inner shell sometimes allows independent turning of the outer shell thereon, even though the inner shell is roughened before assembly.

With the above facts in mind, it is an object of this invention to make the inner shell of such form that independent turning will be definitely prevented.

A further object of the invention is to cut the blanks in such a manner that there is a definitely smaller percentage of waste metal than is possible when the blanks are cut in the shape of a circle.

In manufacturing caps according to this invention, therefore, the inner. shell blank is cut so that its periphery consists of a number of straight sides or chords connected by arcs, the diameter of the latter being the same as that of the normal circular blank out according to the usual practice. In other Words, the inner shell blank is cut in the form of a polygon with the rounded to form arcs. such a blank is stamped and curled, these corners form spaced projections or beads around the edge of the shell, and after it is assembled within the outer shell, these projections serve as keys to lock the two shells against independent turning with respect to each other.

Obviously, the cutting of a blank with four or six oppositely disposed sides permits a layout which effects an important saving in material and the corners of arcuate segments between these sides affords the material to form the locking projections above mentioned.

The invention will be more particularly described with reference to the accompanying drawing, in which:

Fig. 1 shows a suitablelayout from which the blanks may be cut with a considerable saving of material.

Fig. 2 is a plan view of a suitably shaped blank for the inner shell of a cap construction in ac cordance with the invention.

Fig. 3 is a top plan view of a shell drawn from the blank shown in Fig. 1.

Fig. 4 is a side view in section of Fig. 3.

Fig. 5 is a top plan view of the shell after the edge has been curled.

Fig. 6 is a side view in section of Fig. 5.

Fig. 7 is a bottom plan view of the completed cap after the outer shell has been secured thereto.

Fig. 8 is a side view in section of Fig. 7.

In the present embodiment of the invention, the inner shell blank is formed with six equally spaced straight sides or chords It, as shown in Figure 2, and differs in hexagon in that the corners are rounded to form concentric arcs H. The blank is then drawn, as shown in Figures 3 and 4, to form a'crown l2 with the arcs forming spaced brim portions l3. These brim portions are then curled to form a series of beads, as shown at M in Figures 5 and 6, and the panel 20 is raised from the crown l2. The side wall of the crown I2 is formed with a screw thread l5, and may or may not be knurled. The inner shell thus formed is then assembled within the outer shell 11, as shown in Figure 8, with the raised panel 20 and the edge 2| in contact with the top of the outer shell, and the edge I8 of the outer shell is curled about the curled edge of the inner shell including the spaced beads l4. Thus the beads l4 constitute keys to prevent independent turning of one shell with respect to the other.

In cutting blanks for metal caps, it is generally recognized that the best practice is to cut the metal into strips from which the blanks are punched. The layout leaves a definite bridge, usually about 1/16 inch, between adjacent blanks to permit punches to cut the blanks and leave the scrap in one piece for convenience in handling, and to be sure that no loose chips are permitted to fall into the die.

For cutting the six-sided inner shell blanks described above, it is preferred to use the triple die staggered layout shown in Figure 1. Here the blanks are in staggered relation, with the shape from a regular .fore used for the inner tween the centers of adjacent blanks must not be less than twice the radius of the blank plus the j width of the bridge between them,whereas in this embraces such other straight sides l0 of adjacent blanks parallel to each other and separated by a bridge 19. In the .layout for cutting circular blanks, as heretoshells, the distance belayout for the same sized caps, the'distance between centers of adjacent blanks is equal to twice the apothem of the blank plus the width of the bridge Hi. This permits considerable reduction.

in both the width and the'length of the strip from which a given number of the blanks are to be cut, with a corresponding saving in material.

ll not only provides keys Similar resultsr may providing locking means to prevent independent turning and in saving material, if the blanks are formed with four straight sides, or indeed with any even number of sides, with arcuate segments between them. I v 1 While I have shown and described in detail several specific embodimentsof the invention, it is to be understood [purpose of illustration that "this is merely for the and that the invention also 7 modifications as may fall withln'the scope of the appended claims 7 7 Having thus described the invention, what I claim as new and desirev to secure by Letters Patent,is: r

'7 1. The method of producing inner shells for a metal sheet a plurality blankin the metal sheet,

material. A cup form, curling the relatively'short sidestorpro also be obtained, mam;

V relatively short sides double shell capswhich are adapted to fit over an inner shell, which method consists in cutting from of non-circular blanks having relatively long straight sides joined by I relativelyshort sides with the relatively long straight sides'of each blank parallel to an adjarfcent long side of an adjacent blank in thermetal sheet, shaping each blank into cup form, curling the relativelyshort sides/to provide lugs, and

threading the depending wall portion of each cupshaped blank. 7

2. The method of producing inner shells for double shell caps which are adapted to fit over an inner shell, which method consists in cutting from a metal sheet-a plurality of non-circular blanks having relatively long relatively short sides 1n the form of arcs with 7' the relatively long straight sidesfof each blank straight sides joined by parallel to an adjacent long side of an adjacent shaping each blank into videflugs, and threading theidepending wall tion'of each cup-shaped blank.

3. The method of producing inner shellsier double shell caps which are adapted to fitover an inner shell, which method consists in cutting from.

a metal sheet a plurality. of non-circular blanks having relatively long straight sides joined by straight sides of each blank parallel'to an adjawith the relatively long or I cent long side of an adjacent blank. in. the metal 1 sheet, shaping each blank into cup form, curling the relatively short sides 'soi as to leave a continuous. and smooth surface around the bottom peripheral edge of each cup-shaped blank-andso as. to 'providelugs, and threading the depending wall portion of each cup-shaped blank above the V lugs formed by the curled short sides.

"WALTER. KowA-ii. 

